[Asterisk-Users] Comparing mISDN and CAPI for ISDN BRI

[Armin Schindler]

On Fri, 2 Sep 2005, Dias Badekas wrote:
> I was wondering on the choice of chan_capi and chan_misdn.
> What should be the choice for a feature rich use of isdn-bri channel?

It depends on the card you are using (e.g. maybe a special capi driver for 
that card exists like FritzCard) and on the features chan_misdn does provide
(which I cannot tell you).
 
> mISDN is hailed as "the new ISDN stack of the Linux kernel version 2.6"

Hmm, that is not quite correct! 
mISDN is the new stack for ISDN and Linux, but for non-active cards only.
It provides an better interface, which can also provide a CAPI interface and 
an interface to the old isdn4linux.
Actually, CAPI is THE interface on Linux (like it is on Windows), but mISDN 
also provides the internal mISDN interface.
 
> Even though mISDN is  new , looking into the documentation it seems to me that chan_capi implements many
> features including fax.

chan_capi provides fax, because it is defined in the CAPI spec. But it can 
only be used, if the driver providing the CAPI interface will support it.
I don't think mISDN does provide fax yet (but I just don't know the status).
Drivers like 'divas' for Eicon cards do provide the full range of CAPI 
features, but other cards/drivers may do not.
 
> Any consensus between the two chan's ?

For a CAPI-only card, of course, you should use chan_capi.
For cards providing a choice, it depends on what you want to do and what 
features are supported by that channel-driver.

If chan_misdn has a good support for all mISDN features, then I suggest you 
use it without going the 'detour' of CAPI. 
And chan_capi can only do a good job if the driver provides a good CAPI 
interface.

Armin